CULTURE METHODS FOR Medical students Culture methods are done to: Isolate bacteria in pure culture from the clinical specimens and their idintification by various methods. Determination of antibiotic sensitivity. Prepare antigens for serodiagnosis of infective diseases. Maintain stock cultures. Methods to isolate the Bacteria Streak culture Stroke Stab Pour plate Liquid culture Special methods for anaerobic cultures

1. CULTURE
METHODS
PREPARED BY: ROMA GOYAL

2. Culture methods are done to:
• Isolate bacteria in pure culture from the clinical specimens
and their identification by various methods.
• Determination of antibiotic sensitivity.
• Prepare antigens for serodiagnosis of infective diseases.
• Maintain stock cultures.

3. • Streak culture
• Stroke
• Stab
• Pour plate
• Liquid culture
• Special methods for
anaerobic cultures
Methods to isolate the Bacteria

4. STREAK CULTURE
• Used majorly to isolate
the bacteria in pure
culture.
• A platinum or nichrome
(nickel and chromium)
wire loop of 2-4 mm
internal diameter is
used.
•

5. Streak Plate
(Quadrant Streak)

7. Colonies of two different microorganism on agar plate

8. LAWN CULTURE
• Lawn culture are obtained
by flooding the surface of
the surface of the plate with
suspension of the bacterium
• Mainly used for:-
• Antibiotic sensitivity
testing
• Preparation of bacterial
antigens and vaccines.
• Bacteriophage typing

9. STROKE CULTURE
• Done in tubes containing
agar slopes
• Used for:-
• Pure growth of
bacterium.
• For biochemical testing.
• Other diagnostic tests.

10. STAB CULTURE
• It is performed by a straight
wire, charged with culture
material, by puncturing deep
inside the agar.
• It is used to:
• Demonstrate gelatin
liquefaction.
• Oxygen requirement of
the bacterium.
• To maintain stock culture
for preservation of
bacteria.

11. Pour Plate technique

12. Pour plate technique
• Uses:
• To estimate viable count in a suspension.
• To quantitate bacteria in urine culture.

13. LIQUID CULTURE
• Test tubes are
inoculated by a
charged loop.
• Uses are:
• For blood culture.
• For biochemical
examination.
• When large yields of
bacteria are required.

14. Anaerobic Bacterial
Isolation and
Identification Needs
specified conditions

15. Desiccator
• In Desiccator some
oxygen is left.
• Not suitable for fluid
culture.
• Displacement of
oxygen is done with
Hydrogen,Nitrogen,
Helium,Co2

16. Candle Jar
• Inoculated plates are
kept
• Burning candle use
up all oxygen
• But a little o2 is left
• But presence of Co2
stimulates the most
bacterium
16

17. Mac Intosh Fildes Anaerobic Jar
• Contain inlet and
outlet.
• Electrical supply
• Inoculated culture
plates
• When electrified
palladinised asbestos
heating acts as catalyst for
combination of hydrogen
with residual oxygen
causes complete
anaerobiasis

18. Gas pack
• A disposable envelop contains
chemicals which generate
hydrogen and carbon dioxide
on addition of water
• Inoculated plates are kept in
jar
• Water is added hydrogen and
carbon dioxide are liberated
• Presence of cold catalyst in the
envelop permits the
combination of Hydrogen and
oxygen to produce anaerobic
environment
• Indicator is methylene blue
• Colorless when anaerobic
environment.

19. Other Reducing agents
• Reducing agents
O.1% Thiglyclolate
0.1% Ascorbic acid
0.05 % cysteine.
• Cooked meat broth
• It is also known
as Robertson’s
cooked meat
broth(RCM).

20. ANAEROBIC CHAMBER